$THIS is object reference (OREF) -- unique identifier of object in memory. Different objects might have the same OREF during process lifetime

And subscript of local/global can be only numeric or a string -- not an object reference.

So, while indeed $GET(a($THIS)) triggers something wrong, the construction itself is not correct.

Timothy's suggestion converts OREF to string:

if $GET(seen(""_$THIS)) quit

making command correct.

Notice, that in workaround you proposed -- you are using OID, that is unique identifier of object on disk. Different objects cannot have the same OID.

Hi Jochen.

If you have different modules in one namespace I suggest to you to have different Atelier projects for these modules. Then you can have one Git repository to handle all these projects.

With such approach the repository has all the code for the namespace and the code is grouped by projects (modules) inside repository.

Here you can find more details on how you can define Git repository for multiple projects.
https://wiki.eclipse.org/EGit/User_Guide#Creating_a_Git_Repository_for_m...

Regards,
Alexander.